Baen Free Library
Over 100 free science fiction and fantasy novels available for download that the authors have agreed to place online. New books are added regularly.

Barnes & Noble
B&N has many “free” books for download and each Friday they feature “Free Book Friday.”

Calibre
e-book Management software for Linux, OS X and Windows that converts multiple formats to any e-reader’s required format. Also allows users to set up daily “delivery” of many websites content to Calibre.

Feed Books
Publish original e-books by new authors and have a wide selection of public domain e-books.

Free eBooks
Must register first, but also has free magazines as well as e-books.

Google Books
Scroll to the bottom and see the “Best of the Free” – click MORE for additional pages.

Many Books
There are more than 29,000 e-books available here. Includes recommendations and reviews.

Project Gutenberg
Offers over 42,000 free e-books. You can choose among free ePub books or free Kindle books. And they can be downloaded or read online. No fee or registration is required.